Our ISCO projects are focused primarily on the use of Hydrogen Peroxide and Sodium Persulfate (or a combination thereof), since these oxidants form free radicals, which have the strongest oxidizing power of all oxidants. Hydrogen peroxide generates hydroxyl (OH•) radicals and other free radicals in a succession of reactions as shown in the following chemical equations:

Sodium persulfate is activated by one of four methods (peroxide, high pH, iron, or heat) and it results in the formation of sulfate free radicals (SO4-·) and hydroxyl radicals (OH•) as represented in the equations below.

Recent ISCO Projects Designed and Implemented by JAG Consulting

Project

Contaminants

ISCO Chemicals

Gas Station, Silverdale, WA

BTEX, TPH gas,

Stabilized Hydrogen Peroxide and Activated Persulfate

Industrial Site, Ferndale, MI

TCE, VC, Styrene, EB, Toluene

Stabilized Hydrogen Peroxide

Gas Station, Milpitas, CA

BTEX, TPH gas, MTBE

Caustic Activated Sodium Persulfate

Alameda Naval Air Station, CA

TCE, DCE, DCB, CB

Iron Activated Sodium Persulfate

Newport Beach, CA

TCE, VC, DCE, DCB

Caustic Activated Sodium Persulfate

Dry Cleaners, Tarzana, CA

PCE, TCE

Potassium Permanganate

Gas Station, Sun City, CA

BTEX, TPH Gas, MTBE

Caustic Activated Sodium Persulfate

Dry Cleaners, Los Angeles, CA

PCE, TCE

Potassium Permanganate

ISCO Case Studies

ISCO Case Studies performed by JAG Consulting Group at sites throughout California and the Western U.S. are provided in the links below. Included are case studies that have been published in the US EPA newsletter "Technology News and Trends" and in the ITRC Guidance Document for ISCO Injections.

The performance of a Bench Scale Treatability Test is probably the most fiscally prudent task that can be performed while evaluating the technical feasibility of using Chemical Oxidation, Chemical Reduction, or Enhanced Anaerobic Bioremediation for in-situ remediation. A properly performed Bench Scale Test can determine not only whether the technology being evaluated will be effective in the destruction of VOCs in the field, but also whether it will be cost effective. It will also determine whether any adverse side effects may occur. Finally, a properly performed Bench Test will aid in the engineering design of a successful injection project.

Among the many important questions that a well designed Bench Scale Test can answer include the following:

Can the chemical reagent effectively destroy the primary contaminants of concern? This is probably the most important question to answer before spending money on field injections.

What is the optimal dose of chemical reagent to use in the field? Each site has variable soil and water quality characteristics such as high bicarbonate, high sulfate, or high TDS, which might inhibit certain chemical processes. It is important to determine the level of any interferences that may occur so as to not under-dose nor overdose the site.

What will be expected life (duration) of the chemical reagents in the field? The longer the chemical reagents survive in the subsurface the longer time they will have to make contact with and destroy the contaminants of concern.

Will an any adverse side effects occur? Tests can determine whether undesirable daughter products such as 1,2-DCE or vinyl chloride will be generated during bio-degradation of chlorinated compounds. Other tests can determine whether hexavalent chromium generation may occur during oxidation testing.

How buffered are the soils? Sites with highly buffered soils will require larger quantities of acid or base to change the pH. This is important for determining the proper amount of base to add to induce high pH activation of sodium persulfate as well as for neutralizing Bioremediation reagents that might lower the pH of the groundwater.

Can LNAPL or DNAPL be effectively removed? Often times, Bench Tests can confirm that measurable amounts of NAPL can be removed using chemical oxidation.

Is the Soil Oxidant Demand in the moderate range? If the SOD or TOD is elevated, much of the oxidant may be consumed by the naturally occurring organics in the soil and the oxidant will not efficiently destroy contaminants.